1. Field of the Disclosure
(First Disclosure)
The present disclosure relates to a multilane transmission device that transmits a data frame by using a plurality of lanes and a multilane reception device that receives a data frame by using a plurality of lanes.
(Second Disclosure)
The present disclosure relates to a multilane transmission device that transmits a data frame by using a plurality of lanes and a multilane reception device that receives a data frame by using a plurality of lanes.
(Third Disclosure)
The present disclosure relates to a multilane transmission device that divides a signal of a frame format into data blocks, and distributes the data blocks to one or more lanes and transmits the data blocks.
(Fourth Disclosure)
The present disclosure relates to a multilane optical transport system.
(Fifth Disclosure)
The present disclosure relates to a multilane transmission system in which a signal of a frame format is divided into data blocks, and the data blocks are distributed to one or more lanes and transmitted, and a bandwidth change method thereof.
(Sixth Disclosure)
The present disclosure relates to a monitoring technology of transmission quality in a broad area optical transport network.
(Seventh Disclosure)
The present disclosure relates to an individual lane monitoring method in a multilane transmission system in which a signal of a frame format is divided into data blocks, and the data blocks are distributed to one or more lanes and transmitted.
(Eighth Disclosure)
The present disclosure relates to a multilane transmission device and a fault lane notifying method.
(Ninth Disclosure)
The present disclosure relates to a multilane transfer system and a multilane transfer method in which a signal of a frame format is divided into data blocks, and the data blocks are distributed to a plurality of lanes and transmitted from a transmission device to a reception device.
Note that both a “virtual lane” in the first disclosure and the ninth disclosure and a “lane” from the second disclosure to the eighth disclosure indicates a logical lane, and they are not distinguished from each other in the present application.
2. Discussion of the Background Art
(First Disclosure)
As a bit rate increases, it has been under review to configure a network by using an optical switch without performing routing by an electrical processing. This is because when a bit rate of a signal to be switched has a grade from several tens of Gbps to several hundreds of Gbps, there is a large merit due to a feature in which a switching processing of an optical switch does not depend on a bit rate. Here, the optical switch is a switch that is made by a technology such as MEMS (Micro Electro Mechanical Systems) or LCOS (Liquid Crystal On Silicon) and that does not perform O-E-O conversion of a data signal. When this optical switch is used, a function of changing an end node at a wavelength level is provided, and a switching unit can be a wavelength bandwidth or one or more wavelengths (see Non-Patent Literature 1-1).
Non-Patent Literature 1-2 describes a method of distributing a transport frame to a plurality of wavelengths by using a logical lane technology in order to transfer the transport frame at the plurality of wavelengths. Here, a case of transferring an OTU4 (Optical channel Transport Unit 4) frame is described. When the OTU4 frame for carrying a client signal of 100 Gbps is transferred at a plurality of wavelengths, the transfer is performed at 25 Gbps×4 wavelengths or 10 Gbps×10 wavelengths. Twenty (which is a least common multiple of 4 and 10) logical lanes are defined so that the transfer can be performed in both cases. The transfer is performed at a plurality of wavelengths by multiplexing 5 logical lanes into one wavelength when the transfer is performed at 4 wavelengths, and multiplexing 2 logical lanes into one wavelength when the transfer is performed at 10 wavelengths.
In Non-Patent Literature 1-2, virtual concatenation (VCAT) has been standardized in order to make a transport frame capacity variable. At a transmission side, a high-speed client signal received from a client device is demultiplexed, low-speed transport frames are generated using the demultiplexed high-speed client signal as a payload, and the low-speed transport frames are transferred through separate physical lanes. At a reception side, payloads are taken out from low-speed transport frames received through separate physical lanes, the payloads taken out are multiplexed to generate a high-speed client signal, and the high-speed client signal is transferred to the client device.
(Second Disclosure)
In order to economically realize a high-speed data link, various kinds of approaches of logically bundling a plurality of physical lanes have been proposed. For example, in APL (Aggregation at the Physical Layer) used in Non-Patent Literature 2-1, a high-speed data link is economically realized by bundling logically a plurality of physical lanes such that at a transmission side, sequence numbers are added to packets and then the packets are distributed to a plurality of physical lanes, and at a reception side, the packets are rearranged based on the sequence numbers.
(Third Disclosure)
Currently, an OTN (Optical Transport Network) described in Non-Patent Literature 3-1 is being widely used as a wide area optical transport network. An OTN frame has a structure illustrated in FIG. 3-1. A frame is denoted by 4 rows×4080 columns, and 1st to 4080th bytes of the frame correspond to 1st to 4080th columns of a 1st row, 4081st to 8160th bytes correspond to 1st to 4080th columns of a 2nd row, 8161st to 12240th bytes correspond to 1st to 4080th columns of a 3rd row, and 12241st to 16320th bytes correspond to 1st to 4080th columns of a 4th row. A client signal is mapped to an OPU (Optical channel Payload Unit) PLD (Payload) of the 17th to 3824th columns of the frame. An OPU OH (OverHead) is inserted into the 15 to 16th columns, and, for example, information necessary for mapping/demapping of the client signal is included in the 15 to 16th columns. An ODU (Optical channel Data Unit) OH is inserted into the 1st to 14th columns of the 2nd to 4th rows, and path management operation information of an optical channel is included in the 1st to 14th columns of the 2nd to 4th rows. An FA (Frame Alignment) OH including an FAS (Frame Alignment Signal) necessary for frame synchronization and an MFAS (Multiframe Alignment Signal) indicating the position in a multi-frame is inserted into the 1st to 7th column of the 1st row, and an OTU (Optical channel Transport Unit) OH including section monitoring information of an optical channel is inserted into the 8th to 14th columns. A parity check byte for FEC (Forward Error Correction) is added to the 3825th to 4080th columns.
The FAS including OA1s and OA2s are arranged in 1st to 5th bytes of the FA OH, an LLM is arranged in a 6th byte of the FA OH, and the MFAS is arranged in a 7th byte of the FA OH. Here, OA1 is 0b11110110, and OA2 is 0b00101000.
As a technique of economically realizing high-speed optical transmission, 16-byte increment distribution (hereinafter, referred to as OTN-MLD in the present disclosure) of distributing data of an OTU frame of 40 Gbps or 100 Gbps to multiple lanes and performing parallel transmission has been standardized (for example, see Annex C of Non-Patent Literature 3-1). In the OTN-MLD, as illustrated in FIG. 3-2, a frame is divided into 1020 data blocks on a 16-byte basis, and the data blocks are distributed to the lanes one by one. FIG. 3-2 illustrates an example of distributing data blocks to 4 lanes.
A number of a data block including the FAS is set to b=1, and the LLM (Logical Lane Marker) is inserted into the 6th byte of the data block (in FIG. 3-2, the LLM is described in [ ]). By equally distributing the FA OH (the FAS, the LLM, and the MFAS) included in a head data block to all lanes, identifying a lane number and adjusting a delay between lanes can be realized.
In a first frame (LLM=0), the data blocks are distributed as follows:
lane #0: b=1, 5, 9, . . . , 1117
lane #1: b=2, 6, 10, . . . , 1118
lane #2: b=3, 7, 11, . . . , 1119
lane #3: b=4, 8, 12, . . . , 1020
In a second frame (LLM=1), the lanes are rotated, and the data blocks are distributed as follows:
lane #0: b=4, 8, 12, . . . , 1020
lane #1: b=1, 5, 9, . . . , 1117
lane #2: b=2, 6, 10, . . . , 1118
lane #3: b=3, 7, 11, . . . , 1119
In a third frame (LLM=2), the lanes are rotated, and the data blocks are distributed as follows:
lane #0: b=3, 7, 11, . . . , 1119
lane #1: b=4, 8, 12, . . . , 1020
lane #2: b=1, 5, 9, . . . , 1117
lane #3: b=2, 6, 10, . . . , 1118
In a fourth frame (LLM=3), the lanes are rotated, and the data blocks are distributed as follows:
lane #0: b=2, 6, 10, . . . , 1118
lane #1: b=3, 7, 11, . . . , 1119
lane #2: b=4, 8, 12, . . . , 1020
lane #3: b=1, 5, 9, . . . , 1117
Meanwhile, at the reception side, a degree of rotation relative to the frame of LLM=0 can be known by reading the LLM included in the data block in which the FAS is detected in each lane and calculating LLM mod 4. Thus, reconstructing an original frame by compensating for a delay time difference between lanes, then restoring the original positions of the lanes by performing reverse rotation and sequentially connecting the data blocks can be realized.
(Fourth Disclosure)
Currently, an OTN (Optical Transport Network) described in Non-Patent Literature 4-1 is being widely used as a wide area optical transport network. An OTN frame has a structure illustrated in FIG. 4-1. A frame is denoted by 4 rows×4080 columns, and 1st to 4080th bytes of the frame correspond to 1st to 4080th columns of a 1st row, 4081st to 8160th bytes correspond to 1st to 4080th columns of a 2nd row, 8161st to 12240th bytes correspond to 1st to 4080th columns of a 3rd row, and 12241st to 16320th bytes correspond to 1st to 4080th columns of a 4th row. A client signal is mapped to an OPU (Optical channel Payload Unit) PLD (Payload) of the 17th to 3824th columns of the frame. An OPU OH (OverHead) is inserted into the 15 to 16th columns, and, for example, information necessary for mapping/demapping of the client signal is included in the 15 to 16th columns. An ODU (Optical channel Data Unit) OH is inserted into the 1st to 14th columns of the 2nd to 4th rows, and path management operation information of an optical channel is included in the 1st to 14th columns of the 2nd to 4th rows. An FA (Frame Alignment) OH including an FAS (Frame Alignment Signal) necessary for frame synchronization is inserted into the 1st to 7th column of the 1st row, and an OTU (Optical channel Transport Unit) OH including section monitoring information of an optical channel is inserted into the 8th to 14th columns. Redundancy bits for FEC (Forward Error Correction) are added to the 3825th to 4080th columns. Note that since there is a plurality of speeds of 1.25 Gbps to 100 Gbps in the OTN, a suffix k (k=0, 1, 2, 2e, 3, and 4) is added in order to identify the speed (provided that k=0 only for the OPU and the ODU). Note that an OTN of 400 Gbps has not been now standardized, and hereinafter it is temporarily represented by k=5.
In a future optical transport network, an optical path whose capacity can be flexibly made variable according to a variation in traffic is considered to become important. As means of realizing a variable capacity optical path based on an OTN technology, for example, VCAT (Virtual Concatenation) and an OTUflex are mentioned in Non-Patent Literature 4-2.
The details of the VCAT is described in chapter 18 of Non-Patent Literature 4-1, and an LCAS (Link capacity adjustment scheme) which is an approach of making the capacity of the VCAT variable is described in Non-Patent Literature 4-3, and thus the following description will be given based on both the literatures. In the VCAT, an OPUk-Xv configured by virtually coupling number of X OPUks is defined as a variable capacity management frame.
Here, a variable capacity management frame is identical to a variable frame.
As illustrated in FIG. 4-2, the OPUk-Xv includes an OPUk-Xv OH and an OPUk-Xv PLD, the OPUk-Xv OH is arranged in (14X+1)th to 16Xth columns, and the OPUk-Xv PLD is arranged in (16X+1)th to 3824Xth columns. A {(a−1)×X+b}th column of an n-th row of the OPUk-Xv corresponds to a bth column of an ath row of an OPUk #i. Further, a set of multi-frames includes the 256 OPUk-Xvs, and a position of a frame in the multi-frame is identified by using an MFAS (Multiframe Alignment Signal) arranged in a 7th byte of an FA OH.
An individual OPUk OH configuring the OPUk-Xv OH is illustrated in FIG. 4-3. VCOHs (Virtual Concatenation OHs) and the PSI (Payload Structure Identifier) are arranged in a 15th column, and information (for example, stuff control information) according to a mapping format of a client signal is included in a 16th column.
The VCOHs are arranged in 1st to 3rd rows of the 15th column, and denoted as VCOH1, VCOH2, and VCOH3. The VCOHs have 96 bytes (3 bytes×32), and content of the VCOH is as follows (5 bits [0 to 31] of 4th to 8th bits of an MFAS are used as indices of the VCOH1 to the VCOH3).
MFI (Multiframe Indicator) is arranged in VCOH1[0] and VCOH1[1]. The MFI is used for measurement of and compensation for a delay time difference between lanes in combination with an MFAS (see section 18.1.2.2.2.1 of Non-Patent Literature 4-1 and section 6.2.1 of Non-Patent Literature 4-3). Here, a numerical value in brackets of VCOH1[X] is a numerical value (0 to 31) denoted by lower 5 bits of 4th to 8th bits of an MFAS.
SQ (Sequence Indicator) is arranged in VCOH1[4]. The SQ indicates a sequence of coupling an OPUk to an OPUk-Xv (see section 18.1.2.2.2.2 of Non-Patent Literature 4-1 and section 6.2.2 of Non-Patent Literature 4-3).
CTRL (Control) is arranged in 1st to 4th bits of VCOH1[5]. The CTRL is used for transfer of an LCAS control command (see section 18.1.2.2.2.3 of Non-Patent Literature 4-1 and section 6.2.3 of Non-Patent Literature 4-3).
GID (Group Identification) is arranged in a 5th bit of VCOH1[5]. The GID includes a 15-stage pseudo random signal, and is used for identifying a VCG (Virtual Concatenation Group) (see section 18.1.2.2.2.5 of Non-Patent Literature 4-1 and section 6.2.4 of Non-Patent Literature 4-3).
RSA (Re-Sequence Acknowledge) is arranged in a 6th bit of VCOH1[5]. The RSA is a response from a reception side to a transmission side using an RSA bit when a capacity is increased and decrease and a change in the SQ is made (see section of 18.1.2.2.2.6 of Non-Patent Literature 4-1 and section 6.2.7 of Non-Patent Literature 4-3). 7th and 8th bits of VCOH1[5] and VCOH1[6] to VCOH1[31] are spare regions.
The MST (Member Status) is arranged in VCOH2[0] to VCOH2[31]. The MST is a notification of states of all members of a VCG from a reception side to a transmission side (see section 18.1.2.2.2.4 of Non-Patent Literature 4-1 and section 6.2.6 of Non-Patent Literature 4-3).
CRC (Cyclic Redundancy Check) is arranged in VCOH3[0] to VCOH3[31]. The CRC is used for performing error detection on VCOH1 and VCOH2 (see section 18.1.2.2.2.7 of Non-Patent Literature 4-1 and 6.2.5 of Non-Patent Literature 4-3).
As above, VCOH[0] to VCOH[31] are repeated 8 times in a set of multi-frames.
The PSI is arranged in the 4th row of the 15th column. The PSI has 256 bytes, and content of the PSI is as follows (8 bits [0 to 255] of a MFAS are used as indices of the PSI).
A PT (Payload Type) is arranged in PSI [0]. In the case of the VCAT, PT=0x06 (see section 15.9.2.1.1 of Non-Patent Literature 4-1).
vcPT (virtual concatenated Payload Type) is arranged in PSI[1]. The vcPT indicates a payload type of the VCAT. For example, when a payload is a GFP (Generic Framing Procedure), vcPT=0x05 (see section 18.1.2.2.1.1 of Non-Patent Literature 4-1).
CSF (Client Signal Fail) is arranged in a 1st bit of PSI[2]. The CSF is used for notifying a management system of a client signal fault.
2nd to 8th bits of PSI [2] and PSI [3] to PSI [255] are spare regions (see section 18.1.2.2.1.2 of Non-Patent Literature 4-1).
At the transmission side of the VCAT, a client signal is included in an OPUk-Xv PLD, an OPUk-Xv OH and an ODUk-Xv OH are added, and an individual ODUk is included in an appropriate OTUj (j≥k) and transmitted. At the reception side, a delay among a plurality of lanes is compensated for according to the received MFAS and the MFI, an OPUk-Xv is reconfigured according to the SQ of the OPUk, and the client signal is demapped from the OPUk-Xv PLD.
Meanwhile, in the OTUflex, a plurality of frames that is chronologically arrayed are collectively dealt as a variable capacity management frame, and client signals are sequentially contained in a frame and transmitted. When a plurality of lanes is used, each frame is divided in a unit of data blocks, and the data blocks are allocated to a plurality of lanes and transferred.
Note that a variable capacity management frame is identical to a variable frame.
(Fifth Disclosure)
Currently, an OTN (Optical Transport Network) described in Non-Patent Literature 5-1 is being widely used as a wide area optical transport network. An OTN frame has a structure illustrated in FIG. 5-1. A frame is denoted by 4 rows×4080 columns, and 1st to 4080th bytes of the frame correspond to 1st to 4080th columns of a 1st row, 4081st to 8160th bytes correspond to 1st to 4080th columns of a 2nd row, 8161st to 12240th bytes correspond to 1st to 4080th columns of a 3rd row, and 12241st to 16320th bytes correspond to 1st to 4080th columns of a 4th row. A client signal is mapped to an OPU (Optical channel Payload Unit) PLD (Payload) of the 17th to 3824th columns of the frame. An OPU OH (OverHead) is inserted into the 15 to 16th columns, and, for example, information necessary for mapping/demapping of the client signal is included in the 15 to 16th columns. An ODU (Optical channel Data Unit) OH is inserted into the 1st to 14th columns of the 2nd to 4th rows, and path management operation information of an optical channel is included in the 1st to 14th columns of the 2nd to 4th rows. An FA (Frame Alignment) OH including an FAS (Frame Alignment Signal) necessary for frame synchronization, an LLM (Logical Lane Marker) used for lane identification, and an MFAS (Multiframe Alignment Signal) indicating a position in a multi-frame is added to the 1st to 7th columns of the 1st row. An OTU (Optical channel Transport Unit) OH including section monitoring information of an optical channel is inserted into the 8th to 14th columns. A parity check byte for FEC (Forward Error Correction) is added to the 3825th to 4080th columns.
The FAS including OA1s and OA2s are arranged in 1st to 5th bytes of the FA OH, the LLM is arranged in a 6th byte of the FA OH, and the MFAS is arranged in a 7th byte of the FA OH. Here, OA1 is 0b11110110, and OA2 is 0b00101000.
As a technique of economically realizing high-speed optical transmission, OTN-MLD (Multilane Distribution) of distributing data of an OTU frame of 40 Gbps or 100 Gbps to multiple lanes and performing parallel transmission has been standardized (for example, see Annex C of Non-Patent Literature 5-1). In the OTN-MLD, as illustrated in FIG. 5-2, a frame is divided into 1020 data blocks on a 16-byte basis, and the data blocks are distributed to the lanes one by one (the LLM is described in [ ] in the figure). FIG. 5-2 illustrates an example of distributing data blocks to 4 lanes.
In a first frame (LLM=0), data blocks are distributed as follows.
lane #0: b=1, 5, 9, . . . , 1117
lane #1: b=2, 6, 10, . . . , 1118
lane #2: b=3, 7, 11, . . . , 1119
lane #3: b=4, 8, 12, . . . , 1020
In a second frame (LLM=1), the lanes are rotated, and the data blocks are distributed as follows:
lane #0: b=4, 8, 12, . . . , 1020
lane #1: b=1, 5, 9, . . . , 1117
lane #2: b=2, 6, 10, . . . , 1118
lane #3: b=3, 7, 11, . . . , 1119
In a third frame (LLM=2), the lanes are rotated, and the data blocks are distributed as follows:
lane #0: b=3, 7, 11, . . . , 1119
lane #1: b=4, 8, 12, . . . , 1020
lane #2: b=1, 5, 9 . . . , 1117
lane #3: b=2, 6, 10, . . . , 1118
In a fourth frame (LLM=3), the lanes are rotated, and the data blocks are distributed as follows:
lane #0: b=2, 6, 10, . . . , 1118
lane #1: b=3, 7, 11, . . . , 1119
lane #2: b=4, 8, 12, . . . , 1020
lane #3: b=1, 5, 9, . . . , 1117
FIG. 5-3 illustrates a transmitting unit of a multilane transmission device using the OTN-MLD. The transmitting unit of the multilane transmission device includes a mapping unit 1, an OH processing unit 2, an interleaving unit 3, encoding units 4-1 to 4-16, a deinterleaving unit 5, a scrambling unit 6, a data block dividing unit 7, and a lane number deciding unit 8. Hereinafter, a case in which the number M of lanes is 16 will be described.
The mapping unit 1 maps a client signal to an OPU PLD.
The OH processing unit 2 adds an overhead to an OPU frame. Examples of the overhead include an FA OH, an OTU OH, and an ODU OH. Here, as illustrated in FIG. 5-1, the LLM is arranged in a 6th byte of the FA OH.
The interleaving unit 3 performs 16-byte interleaving on a frame of 4 rows×3824 columns in which the overhead is added to the OPU frame for each row (3824 bytes).
The encoding units 4-1 to 4-16 encode sub-row data (239 bytes) which have been subjected to byte interleaving, and outputs sub-row data (255 bytes) to which a 16-byte parity check is added.
The deinterleaving unit 5 deinterleaves the encoded sub-row data, and outputs an encoded OTU frame of 4 rows×4080 columns.
The scrambling unit 6 scrambles all regions of the FEC-coded OTU frame of 4 rows×4080 columns except the FAS.
The data block dividing unit 7 divides the scrambled OTU frame into 16-byte data blocks.
The lane number deciding unit 8 decides a lane number, and outputs data blocks obtained by dividing the frame to the corresponding lane.
Here, a lane number m (m=0 to M−1) of a lane to which a head data block including the FAS is output is decided by:m=LLM mod M 
In the case of the remaining data blocks, when m′ is an immediately previous lane number, the lane number m is decided by:m=(m′+1)mod M 
FIG. 5-4 illustrates configuration of a receiving unit of the multilane transmission device. The receiving unit of the multilane transmission device includes a lane identifying & delay difference compensating unit 10, an OTU frame reconfiguring unit 11, a descrambling unit 12, an interleaving unit 13, decoding units 14-1 to 14-16, a deinterleaving unit 15, an OH processing unit 16, and a demapping unit 17. FIG. 5-5 illustrates configuration of the lane identifying & delay difference compensating unit 10. The lane identifying & delay difference compensating unit 10 includes FA OH detecting units 20-1 to 20-M, a delay comparing unit 21, and delay adjusting units 22-1 to 22-M.
The FA OH detecting units 20-1 to 20-M find the head data block including the FAS, and read the FAS, the LLM, and the MFAS. The delay comparing unit 21 determines a delay time difference, and compensates for the delay time difference by using the delay adjusting units 22-1 to 22-M as will be described in the following example. FIGS. 5-6(a) and 5-6(b) illustrate an example of compensating for a delay difference in the case of 4 lanes.
In the case in which assuming that a head position of a data block of MFAS=0 received through a lane #0 is a reference, when there is no delay time difference between lanes, a head position of a data block of MFAS=1 received through a lane #1, a head position of a data block of MFAS=2 received through a lane #2, a head position of a data block of MFAS=3 received through a lane #3 should be delayed by 4080 bytes, 8160 bytes, and 12240 bytes, respectively. However, since signals of the respective lanes are transmitted through light of different wavelengths, a delay time difference occurs due to influence of dispersion or the like.
Here, when the head positions of the data blocks of MFAS=1, MFAS=2, and MFAS=3 with the head position of the data block of MFAS=0 as the reference are assumed to have been delayed by 3980 bytes, 8460 bytes, and 12440 bytes, respectively, as illustrated in FIG. 5-6(a), it is understood that a delay time difference of −100 bytes, a delay time difference of +300 bytes, and a delay time difference of +200 bytes with respect to an expected delay time have occurred in the lane #1, lane #2, and lane #3, respectively. Then, when a delay of 300 bytes, a delay of 400 bytes, and a delay of 100 bytes are given to the delay adjusting unit of the lane #0, the delay adjusting unit of the lane #1, and the delay adjusting unit of the lane #3, respectively, all lanes can be conformed to the lane #2 that has the largest delay as illustrated in FIG. 5-6(b).
The OTU frame reconfiguring unit 11 receives the data blocks of the respective lanes which have been subjected to delay time difference compensation, restores the original sequence of the data blocks of the respective lanes based on the lane numbers identified by the lane identifying & delay difference compensating unit 10, and reconfigures an OTU frame of 4 rows×4080 columns.
The descrambling unit 12 descrambles all regions of the reconfigured OTU frame except the FAS.
The interleaving unit 13 performs 16-byte interleaving on the OTU frame of 4 rows×4080 columns for each row (4080 bytes).
The decoding units 14-1 to 14-16 decode the byte-interleaved sub-row data (255 bytes), and outputs error-corrected sub-row data (238 bytes).
The deinterleaving unit 15 deinterleaves the decoded sub-row data, and outputs an error-corrected frame of 4 rows×3824 columns.
The OH processing unit 16 outputs an OPU frame in which the overheads such as the FA OH, the OTU OH, the LM OH, and the ODU OH are eliminated from the error-corrected frame of 4 rows×3824 columns.
The demapping unit 17 demaps the client signal from the OPU PLD based on information of the OPU OH, and outputs the client signal.
(Sixth Disclosure)
Currently, an OTN (Optical Transport Network) described in Non-Patent Literature 6-1 is being widely used as a wide area optical transport network. An OTN frame has a structure illustrated in FIG. 6-1. A frame is denoted by 4 rows×4080 columns, and 1st to 4080th bytes of the frame correspond to 1st to 4080th columns of a 1st row, 4081st to 8160th bytes correspond to 1st to 4080th columns of a 2nd row, 8161st to 12240th bytes correspond to 1st to 4080th columns of a 3rd row, and 12241st to 16320th bytes correspond to 1st to 4080th columns of a 4th row.
A client signal is mapped to an OPU (Optical channel Payload Unit) PLD (Payload) of the 17th to 3824th columns of the frame.
An OPU OH (OverHead) is inserted into the 15 to 16th columns, and, for example, information necessary for mapping/demapping of the client signal is included in the 15 to 16th columns.
An ODU (Optical channel Data Unit) OH is inserted into the 1st to 14th columns of the 2nd to 4th rows, and path management operation information of an optical channel is included in the 1st to 14th columns of the 2nd to 4th rows.
An FA (Frame Alignment) OH including an FAS (Frame Alignment Signal) necessary for frame synchronization and an MFAS (Multiframe Alignment Signal) indicating the position in a multi-frame is inserted into the 1st to 7th column of the 1st row, and an OTU (Optical channel Transport Unit) OH including section monitoring information of an optical channel is inserted into the 8th to 14th columns. A parity check byte for FEC (Forward Error Correction) is added to the 3825th to 4080th columns.
In the OTN, SM (Section Monitoring) OH and PM (Path Monitoring) OH are defined in the OTU OH and the ODU OH, respectively, for transmission quality management.
As illustrated in FIG. 6-2, the SM is arranged in 8th to 10th columns of a 1st row (see section 15.7.2.1 of Non-Patent Literature 6-1).
A TTI (Trail Trace Identifier) is a sub field arranged in a 1st byte of the SM OH. The TTI includes an SAPI (Source Access Point Identifier) indicating a section monitoring starting point and a DAPI (Destination Access Point Identifier) indicating a section monitoring ending point (see sections 15.2 and 15.7.2.1.1 of Non-Patent Literature 6-1).
BIP-8 (Bit Interleaved Parity-8) is a sub field arranged in a 2nd byte of the SM OH. As illustrated in FIG. 6-3, at a transmission side, OPU data of a second previous frame is interleaved, an 8-bit parity (BIP-8) is calculated, and the 8-bit parity (BIP-8) is inserted into the BIP-8 sub field of the SM OH. At a reception side, a value obtained by calculating the BIP-8 from the OPU data is compared with a value of the BIP-8 sent through the BIP-8 sub field of the SM OH, and an error occurring in a section monitoring zone is detected (see section 15.7.2.1.2 of Non-Patent Literature 6-1).
As illustrated in FIG. 6-4, the PM OH is arranged in 10th to 12th columns of a 3rd row (see section 15.8.2.1 of Non-Patent Literature 6-1).
The TTI is a sub field arranged in a 1st byte of the PM OH. The TTI includes an SAPI indicating a path monitoring starting point and a DAPI indicating a path monitoring ending point (see sections 15.2 and 15.8.2.1.1 of Non-Patent Literature 6-1).
The BIP-8 is a sub field arranged in a 2nd byte of the PM OH. As illustrated in FIG. 6-5, at a transmission side, OPU data of a second previous frame is interleaved, an 8-bit parity (BIP-8) is calculated, and the 8-bit parity (BIP-8) is inserted into the BIP-8 sub field of the PM OH. At a reception side, a value obtained by calculating the BIP-8 from the OPU data is compared with a value of the BIP-8 sent through the BIP-8 sub field of the PM OH, and an error occurring in a path monitoring zone is detected (see section 15.8.2.1.2 of Non-Patent Literature 6-1).
As described above, in the OTN, counting the number of errors occurring in the section monitoring zone and the path monitoring zone by using the BIP-8s in the SM OH and the PM OH can be realized.
(Seventh Disclosure)
Currently, an OTN (Optical Transport Network) described in Non-Patent Literature 7-1 is being widely used as a wide area optical transport network. An OTN frame has a structure illustrated in FIG. 7-1. A frame is denoted by 4 rows×4080 columns, and 1st to 4080th bytes of the frame correspond to 1st to 4080th columns of a 1st row, 4081st to 8160th bytes correspond to 1st to 4080th columns of a 2nd row, 8161st to 12240th bytes correspond to 1st to 4080th columns of a 3rd row, and 12241st to 16320th bytes correspond to 1st to 4080th columns of a 4th row. A client signal is mapped to an OPU (Optical channel Payload Unit) PLD (Payload) of the 17th to 3824th columns of the frame. An OPU OH (OverHead) is inserted into the 15 to 16th columns, and, for example, information necessary for mapping/demapping of the client signal is included in the 15 to 16th columns. An ODU (Optical channel Data Unit) OH is inserted into the 1st to 14th columns of the 2nd to 4th rows, and path management operation information of an optical channel is included in the 1st to 14th columns of the 2nd to 4th rows. An FA (Frame Alignment) OH including an FAS (Frame Alignment Signal) necessary for frame synchronization and an MFAS (Multiframe Alignment Signal) indicating the position in a multi-frame is inserted into the 1st to 7th column of the 1st row, and an OTU (Optical channel Transport Unit) OH including section monitoring information of an optical channel is inserted into the 8th to 14th columns. A parity check byte for FEC (Forward Error Correction) is added to the 3825th to 4080th columns.
The FAS including OA1s and OA2s are arranged in 1st to 5th bytes of the FA OH, an LLM is arranged in a 6th byte of the FA OH, and the MFAS is arranged in a 7th byte of the FA OH. Here, OA1 is 0b11110110, and OA2 is 0b00101000.
In the OTN, an SM (Section Monitoring) OH and a PM (Path Monitoring) OH are defined in an OTU OH and an ODU OH, respectively, for transmission quality management.
As illustrated in FIG. 7-2, an SM OH is arranged in 8th to 10th columns of a 1st row (see section 15.7.2.1 of Non-Patent Literature 7-1).
The TTI (Trail Trace Identifier) is a sub field arranged in a 1st byte of the SM OH. The TTI includes an SAPI (Source Access Point Identifier) indicating a section monitoring starting point and a DAPI (Destination Access Point Identifier) indicating a section monitoring ending point (see sections 15.2 and 15.7.2.1.1 of Non-Patent Literature 7-1).
The BIP-8 (Bit Interleaved Parity-8) is a sub field arranged in a 2nd byte of the SM OH. As illustrated in FIG. 7-3, at a transmission side, OPU data of a second previous frame is interleaved, an 8-bit parity (BIP-8) is calculated, and the 8-bit parity (BIP-8) is inserted into the BIP-8 sub field of the SM OH. At a reception side, a value obtained by calculating the BIP-8 from the OPU data is compared with a value of the BIP-8 sent through the BIP-8 sub field of the SM OH, and an error occurring in a section monitoring zone is detected (see section 15.7.2.1.2 of Non-Patent Literature 7-1).
As illustrated in FIG. 7-4, the PM OH is arranged in 10th to 12th columns of a 3rd row (see section 15.8.2.1 of Non-Patent Literature 7-1).
The TTI is a sub field arranged in a 1st byte of the PM OH. The TTI includes an SAPI indicating a path monitoring starting point and a DAPI indicating a path monitoring ending point (see sections 15.2 and 15.8.2.1.1 of Non-Patent Literature 7-1).
The BIP-8 is a sub field arranged in a 2nd byte of the PM OH. As illustrated in FIG. 7-5, at a transmission side, OPU data of a second previous frame is interleaved, an 8-bit parity (BIP-8) is calculated, and the 8-bit parity (BIP-8) is inserted into the BIP-8 sub field of the PM OH. At a reception side, a value obtained by calculating the BIP-8 from the OPU data is compared with a value of the BIP-8 sent through the BIP-8 sub field of the PM OH, and an error occurring in a path monitoring zone is detected (see section 15.8.2.1.2 of Non-Patent Literature 7-1).
As described above, in the OTN, counting the number of errors occurring in the section monitoring zone and the path monitoring zone using the BIP-8s in the SM OH and the PM OH can be realized.
(Eighth Disclosure)
Currently, an OTN (Optical Transport Network) is being widely used as a wide area optical transport network (for example, see Non-Patent Literature 8-1). An OTN frame has a structure illustrated in FIG. 8-9. FIG. 8-9 is a diagram illustrating an OTN frame structure. A frame is denoted by 4 rows×4080 columns, and 1st to 4080th bytes of the frame correspond to 1st to 4080th columns of a 1st row, 4081st to 8160th bytes correspond to 1st to 4080th columns of a 2nd row, 8161st to 12240th bytes correspond to 1st to 4080th columns of a 3rd row, and 12241st to 16320th bytes correspond to 1st to 4080th columns of a 4th row.
A client signal is mapped to an OPU (Optical channel Payload Unit) PLD (Payload) of the 17th to 3824th columns of the frame. An OPU OH (OverHead) is inserted into the 15 to 16th columns, and, for example, information necessary for mapping/demapping of the client signal is included in the 15 to 16th columns. An ODU (Optical channel Data Unit) OH is inserted into the 1st to 14th columns of the 2nd to 4th rows, and path management operation information of an optical channel is included in the 1st to 14th columns of the 2nd to 4th rows. An FA (Frame Alignment) OH including an FAS (Frame Alignment Signal) necessary for frame synchronization and an MFAS (Multiframe Alignment Signal) indicating the position in a multi-frame is inserted into the 1st to 7th column of the 1st row, and an OTU (Optical channel Transport Unit) OH including section monitoring information of an optical channel is inserted into the 8th to 14th columns. A parity check byte for FEC (Forward Error Correction) is added to the 3825th to 4080th columns.
In the OTN, an SM (Section Monitoring) OH and a PM (Path Monitoring) OH are defined in an OTU OH and an ODU OH, respectively, for transmission quality management. As illustrated in FIG. 8-10, an SM OH is arranged in 8th to 10th columns of a 1st row. FIG. 8-10 is a diagram illustrating the position of the SM OH in the OTU OH. The TTI (Trail Trace Identifier) is a sub field arranged in a 1st byte of the SM OH. The TTI includes an SAPI (Source Access Point Identifier) indicating a section monitoring starting point and a DAPI (Destination Access Point Identifier) indicating a section monitoring ending point.
The BIP-8 (Bit Interleaved Parity-8) is a sub field arranged in a 2nd byte of the SM OH. At a transmission side, OPU data of a second previous frame is interleaved, an 8-bit parity (BIP-8) is calculated, and the 8-bit parity (BIP-8) is inserted into the BIP-8 sub field of the SM OH. At a reception side, a value obtained by calculating the BIP-8 from the OPU data is compared with a value of the BIP-8 sent through the BIP-8 sub field of the SM OH, and an error occurring in a section monitoring zone is detected.
The BEI/BIAE (Backward Error Indication and Backward Incoming Alignment Error) is a sub field arranged in 1st to 4th bits of a 3rd byte of the SM OH. “0000” to “1000” are used when a notification of an error count number (0 to 8) detected in the BIP-8 in the section monitoring zone (BEI) is given to an upper stream, and “1011” is used when a notification of a frame synchronization error is given to the upper stream (BIAE).
The BDI (Backward Defect Indication) is a sub field arranged in a 5th bit of the 3rd byte of the SM OH. When a notification indicating that a fault has been detected in the section monitoring zone is given to the upper stream, the BDI is “1,” and otherwise, the BDI is “0.”
The IAE (Incoming Alignment Error) is a sub field arranged in a 6th bit of the 3rd byte of the SM OH. When a notification of a frame synchronization error is given to an end node, the IAE is “1,” and otherwise, the IAE is “0.” Note that 7th to 8th bits (“00”) of the 3rd byte of the SM OH are spare regions.
As described above it can be realized to give a notification indicating that a fault or a frame synchronization error has occurred in section monitoring from the reception side to the transmission side by using the BEI/BIAE and the BDI in the SM OH in the OTN.
(Ninth Disclosure)
In recent years, as a bit rate of a client signal increases, large capacity communication by multilane transfer has been under review in order to transfer a client signal that has exceeded a bit rate of one wavelength. As multilane transfer, a scheme of performing multilane transfer by distributing blocks obtained by dividing an OTUk frame on a 16-byte basis to a plurality of lanes is described in Annex C of the international standard ITU-T G.709 which is an OTN interface standard (for example, see Non-Patent Literature 9-1), and operation thereof is described in the international standard ITU-T G.798 (for example, see Non-Patent Literature 9-2). Here, an OTUk frame is an OTUk of G.709, and is assumed to be a frame having a frame structure of 4×4080 bytes. Further, in multilane transfer intended for realizing an elastic optical path network (for example, see Non-Patent Literature 9-3), multilane transfer that allows the number of lanes to be changed according to a transfer capacity of the flow is required in an interface of a transmission device. A flow in the specification of the present application is assumed to be information transferred with the same end node or QoS priority. As an example of a frame scheme and a transfer scheme of realizing multilane transfer according to a transfer capacity, Patent Literature 9-1 is proposed.
Further, a case can be mentioned in which as the speed of an interface increases, a fault occurs, and influence on communication when transfer is stopped increases. In order to suppress this influence, there is a technology of performing shrink operation, or protection of securing a transfer capacity by using a free lane, and in multilane transfer a mechanism of performing transfer by using a normal lane without performing transfer through a lane having a fault has been under review. In the specification of the present application, a lane refers to a virtual lane. A virtual lane in the specification of the present application refers to a lane used for transferring data in conformity to a transfer speed of a physical lane even when the transfer speed of the physical lane is changed. By arbitrarily multiplexing one or more virtual lanes, transfer is performed in conformity to the changed transfer speed of the physical lane. For example, transfer using a physical lane of 10 Gbps, 25 Gbps, or 100 Gbps can be performed by multiplexing 2 virtual lanes, 5 virtual lanes, or 20 virtual lanes each of which is 5 Gbps. In addition, the shrink operation refers to operation in which while multilane transfer is being performed, when a fault has occurred in one of the lanes and thus the multilane transfer cannot be performed, transfer is performed at a decreased transfer speed by using a lane having no fault through which transfer can be normally performed. Further, the protection refers to operation in which while multilane transfer is being performed, when a fault has occurred in some lanes and thus the multilane transfer cannot be performed, by switching from a lane having a fault to an unused normal lane, transfer is performed at the same transfer speed as before the fault occurs.
In an OTN interface of the related art, monitoring using an OTUk frame is performed for each wavelength, and a physical lane to be used for transfer is managed by a frame. Here, a physical lane refers to a wavelength, or one channel in super channel transmission.
Further, the multilane transfer in Annex C of Non-Patent Literature 9-1 is a scheme of dividing an OTUk frame into 1020 blocks on a 16-byte basis, distributing the blocks to a plurality of lanes, and performing transfer. State monitoring of each lane used for the multilane transfer is described in Non-Patent Literature 9-2, and in the multilane transfer, a plurality of lanes is monitored, and it is determined whether or not reconstructing a frame from the plurality of lanes is possible. This state monitoring is performed by monitoring LOR (Loss of Recovery), LOL (Loss of Lane Alignment), or the like, specifically, by checking a value of an LLM (Logical Lane Marker). When a value of the LLM becomes correct five times consecutively in a unit of 16320 bytes, it is regarded as an IR (In-Recovery) state, and when a value of the LLM is incorrect, it is determined to be an OOR (Out-of-Recovery) state indicating a state in which a frame cannot be reconstructed from a plurality of lanes. When the OOR state is continued for 3 ms, it is determined to be the LOR (Loss of Recovery) state. Here, the LLM is a word described in G.709 Annex C, and is a value positioned at a 6th byte of a frame alignment overhead and necessary for reconstructing a frame from a plurality of lanes in multilane transfer.
In addition, a monitoring/management layer structure of multilane transfer in Annex C of Non-Patent Literature 9-1 is illustrated in FIG. 9-14. An OTUk frame is divided into an OTL (Optical Channel Transport Lane) corresponding to a physical lane and transferred. In a monitoring/management model, a structure of managing an individual physical lane OTL through an OTLC (Optical Transport Lane Carrier) serving as a transfer medium, and managing an OTLCG (Optical Transport Lane Carrier Group) in which OTLCs are collected, through an OPSM (Optical Physical Section Multilane) is provided.
Further, Patent Literature 9-1 describes a multilane transfer scheme that allows a transfer capacity to be changed through a mechanism in which the number of multiple lanes used in transferring 16-byte blocks can be changed and a frame can be reconstructed even when the number of lanes is changed.